Magnetic structure and crystalline electric field effects in the triangular antiferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>CePtA</mml:mi><mml:msub><mml:mi mathvariant="normal">l</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:mi mathvariant="normal">G</mml:mi><mml:msub><mml:mi mathvariant="normal">e</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Soohyeon Shin, Vladimir Pomjakushin, L. Keller, P. F. S. Rosa, U. Stuhr, Ch. Niedermayer, Romain Sibille, S. Tóth, J. Kim, Harim Jang, Seowoo Son, H.-O. Lee, Tian Shang, M. Medarde, E. D. Bauer, M. Kenzelmann, Tuson Park
Abstract
Kondo metal $\mathrm{CePtA}{\mathrm{l}}_{4}\mathrm{G}{\mathrm{e}}_{2}$ exhibits long-range antiferromagnetic order below 2.3 K. Neutron powder-diffraction experiments reveal that Ce moments order antiferromagnetically with an incommensurate ordering wave vector $\mathbit{k}=(1.39,0,0.09)$. Inelastic neutron powder scattering experiments show a magnetic excitation at 14.5 meV, which corresponds to the first excited state due to the crystalline electric field splitting of the ground-state multiplet of $\mathrm{C}{\mathrm{e}}^{3+}$. The temperature and field dependence of the magnetization of $\mathrm{CePtA}{\mathrm{l}}_{4}\mathrm{G}{\mathrm{e}}_{2}$ is consistent with a doublet ground state with a dominant $|{j}_{\mathrm{z}}=1/2\ensuremath{\rangle}$ character and a first excited doublet $|{j}_{\mathrm{z}}=3/2\ensuremath{\rangle}$ at 14.5 meV.